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Vitamin B12

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

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Vitamin B12, or cyanocobalamin, is a group of cobalt-containing water-soluble vitamins. They are coenzymes necessary for red blood cell production - folate polyglutamate is the major red cell form of folate. It is crucial for neurologic function and DNA synthesis.

Vitamin B12 is derived primarily from food of animal origin, including dairy products.

Absorption of B12 from the gastrointestinal tract is dependent on acid and intrinsic factor secreted by the stomach’s parietal cells.

The recommended dietary allowance (RDAs) for vitamin b12 in the adult is 2.4 micrograms (2). A normal liver stores about 3 mg which is sufficient for several years.

Notes:

  • In humans, only two enzymatic reactions are known to be dependent on vitamin B12:
    • methylmalonic acid is converted to succinyl-CoA using vitamin B12 as a cofactor
      • vitamin B12 deficiency can lead to increased levels of serum methylmalonic acid
    • homocysteine is converted to methionine by using vitamin B12 and folic acid as cofactors
      • therefore a deficiency of vitamin B12 or folic acid may lead to increased homocysteine levels

Reference:

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The content herein is provided for informational purposes and does not replace the need to apply professional clinical judgement when diagnosing or treating any medical condition. A licensed medical practitioner should be consulted for diagnosis and treatment of any and all medical conditions.

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